Liquid fuel supply system for prime movers or furnaces



Nov. 10, 1953 RlGHTON 2,658,565

LIQUID FUEL SUPPLY SYSTEM FOR PRIME MOVERS OR FURNACES Filed Nov. 9, 1951 2 Sheets-Sheet l L21 u elwtor Nov. 10, 1953 J. J. RIGHTON 2,658,565

LIQUID FUEL SUPPLY SYSTEM FOR PRIME MOVERS 0R FURNACES Filed Nov. 9, 1951 2 Sheets-Sheet 2 n. ..IIIV

Patented Nov. 10, 1953 LIQUID FUEL SUPPLY SYSTEM FOR PRIME MOVERS R FURNACES Joseph John Righton, Acocks Green, Birmingham, England, assignor to Joseph Lucas, Limited, Birmingham, England Application November 9, 1951, Serial No. 255,560

Claims priority, application Great Britain November 14, 1950 3 Claims. (01; 158 -3624) The invention relates to systems for supplying liquid fuel to the burners of prime movers or furnaces, of the kind in which the burner is of the swirl-chamber type, and in which the liquid. fuel can be supplied to the burner at a rate in excess of the quantity to be consumed, in order to maintain an adequate rate of swirl in the swirl chamher, the excess being returned to the system.

The object of the invention is to provide an improved system whereby the rate of return of the excess fuel can 'be controlled in a more satisfactory manner than heretofore.

The invention comprises a system having in combination, a main fuel supply pump, a manually operable control means between the main pump and the burner, an excess fuel by-pass interconnecting the burner swirl chamber (or chambers) and a point in the supply line between the manually operable control means and the burner, a variable delivery pump in the by-pass, and means responsive to a fuel pressure difference in the system for controlling the action of the by-pass pump.

Alternatively the by-pass may be provided with a fixed-delivery pump and a spill valve controlled by the said pressure-responsive means.

In the accompanying drawings:

Figure 1 is a diagram illustrating one embodiment of the invention and Figure 2 is a diagram illustrating a modification of the arrangement shown in Figure 1.

Figure 3 is a diagram illustrating an alternative embodiment of the invention.

In the arrangement shown in Figure 1, for supplying liquid fuel from a storage reservoir a to a burner in the combustion chamber of a jet engine or gas turbine, there is provided a main pump 1) for supplying the fuel to the burner. The latter may comprise a single nozzle 0 having therein a swirl chamber (2 or a plurality of such nozzles. In the pi e line 6 between the said pump 1) and the burner is provided any convenient manually adjustable throttle indicated by f, and I 2 control of the throttle J, the other side of the piston being acted on by the pressure of a spring.

In the by-pass line 9 is provided any convenient variable delivery pump Z which (in the example shown) is similar to the pump 1), the piston 7' acting on the swash plate being operable in one direction for reducing the output of the pump by liquid pressure derived from a point in the pipe 6 between the throttle f and burner. The piston 7' is movable in the other direction for increasing the ouput of the pump Z by a spring m, the end of the cylinder n containing the spring being connected by a pipe to the inlet of the pump 27. Alternatively, and as shown in Figure 2, the piston 7' may be subject (in addition to the pressure of the spring m) to a liquid pressure difference existing at the opposite sides of a restricted orifice o in the pipe line e between the throttle and burner.

By means of the variable pump Z the quantity of fuel returned from the swirl chamber or chambers d of the burner nozzle or nozzles is variable in response to a variable pressure in the fuel supply pipe e, increase of the rate of supply of fuel to the burner being accompanied by a reduction of the return flow through the pump Z.

In the alternative arrangement shown in Figure 3, the by-pass g is provided with a fixeddelivery pump p with which is associated a spill valve q which is actuated by a piston 1 subject to the action of an appropriate liquid pressure and the pressure of a spring s. In the example shown, one end of the cylinder t containing the piston is connected to a point in the fuel pipe e between the throttle and the burner, and the other end is connected by a pipe u to the tank a. The valve (1 allows spillage from the by-pass pipe 9 to be returned to the inlet side of the pump p. It is desired to maintain the liquid pressure difference acting on the piston r substantially constant, and. this is effected by arranging that with increase of rate of supply of fuel to the burner, the rate of spillage past the valve q is appropriately increased and vice versa.

Whilst the invention is primarily intended for use with prime movers, it may also be applied to systems for supplying liquid fuel to furnaces for industrial or other purposes.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A liquid fuel supply system for a prime mover or furnace comprising, in combination, a burner having a swirl chamber, a main fuel supply pump, a supply conduit between the main pump and the burner for supplying fuel to the latter, manually operable control means in said supply conduit, means forming a by-pass conduit between the swirl chamber and a point in the supply conduit between the manually operable control means and the burner, a pump in the bypass conduit for returning excess fuel from the spill chamber, and means responsive to a fuel pressure difference in the system for reducing the rate of return flow in the by-passconduit in accordance with an increase in the rate of supply of fuel to the burner and for increasing the rate of return flow in said-by-pass conduit in accordance with a decrease in the rate of flow of fuel to the burner.

2. A fuel supply system according to claim 1, in which the means responsive to a fuel pressure Number in which'the'means responsive to a fuel pressure in the system is responsive to the pressure difference existing across a restricted orifice in the fuel supply conduit at a point between the manually'operable control means and the burner.

JOSEPH JOHN RIGHTON.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Ifield Sept. 19, 1950 Lawrence et a1 Sept. 4, 1951 

